Methods and systems for significance coefficient coding in video compression

Abstract

A method for decoding significance coefficients in an encoded video sequence is described. An encoded video bitstream is received. Codebook table information is retrieved from the bitstream. Significance symbols are decoded using the retrieved codebook table information. Significance coefficients are decoded using the significance symbols. A plurality of transform coefficients is dequantized. An inverse transform is applied to a residual signal. A video sequence is constructed. A method for coding significance coefficients in a video sequence is also described.

What is claimed is: 
     
       1. A method of coding significance coefficients in a video sequence comprising:
 receiving a video sequence in an electronic video coder; 
 constructing a prediction of an original video signal in a current frame from the video sequence; 
 forming a residual signal by subtracting the prediction of the original video signal from the original video signal in the current frame; 
 applying a transform to the residual signal; 
 quantizing a plurality of transform coefficients; 
 selecting a codebook from a plurality of codebooks to code at least one of a significance run and an end-of-block; 
 coding, using the selected codebook by the video coder, the at least one of the significance run or the end-of-block to generate a portion of an encoded video bitstream; and 
 outputting the generated portion of the encoded video bitstream from the electronic video coder. 
 
     
     
       2. The method of  claim 1 , wherein coding the at least one of the significance run or end-of-block further comprises coding the significance run and the end-of-block using the selected codebook. 
     
     
       3. The method of  claim 1 , further comprising coding codebook table information with a video slice. 
     
     
       4. The method of  claim 3 , wherein the codebook table information comprises a codebook selection table. 
     
     
       5. The method of  claim 3 , wherein the codebook table information comprises a codebook selection table with each entry corresponding to each pair of coding cycle numbers and a LEBL (last encoded coefficient in the base layer) position. 
     
     
       6. The method of  claim 3 , wherein the codebook table information comprises a codebook selection table with each entry corresponding to only the coding cycle number. 
     
     
       7. The method of  claim 6 , further comprising coding the codebook selection table as a one-dimensional codebook selection array. 
     
     
       8. The method of  claim 7 , further comprising coding a variable that specifies a number of the codebook selection table entries that are explicitly coded, wherein the variable is followed by codebook selectors, wherein each codebook selector is coded using a variable length code. 
     
     
       9. The method of  claim 3 , wherein the codebook table information comprises a table shape and a table dimension. 
     
     
       10. The method of  claim 9 , wherein the table shape is rectangular. 
     
     
       11. The method of  claim 9 , wherein the table shape is triangular. 
     
     
       12. The method of  claim 1 , wherein a codebook selection table is dynamically determined from a statistics estimation. 
     
     
       13. The method of  claim 1 , wherein a codebook selection table is dynamically determined from a neighboring correlation. 
     
     
       14. The method of  claim 1 , wherein among the plurality of codebooks, one codebook is a shifted version of another codebook. 
     
     
       15. The method of  claim 1 , further comprising:
 pruning a codebook selection table to provide a pruned codebook selection table; and 
 coding the pruned codebook selection table with a video slice. 
 
     
     
       16. A method of decoding significance coefficients in an encoded video sequence comprising:
 receiving an encoded video bitstream in an electronic video decoder; 
 retrieving codebook table information from the bitstream; 
 decoding significance symbols using the retrieved codebook table information; 
 decoding significance coefficients using the significance symbols; 
 dequantizing a plurality of transform coefficients; 
 applying an inverse transform to a residual signal; 
 constructing a video sequence in the video decoder; and 
 outputting the constructed video sequence from the electronic video decoder. 
 
     
     
       17. The method of  claim 16 , further comprising decoding codebook table information from a slice. 
     
     
       18. The method of  claim 17 , wherein the codebook table information comprises a codebook selection table. 
     
     
       19. The method of  claim 18 , wherein the codebook table information comprises a codebook selection table mapping cycle number and a LEBL (last encoded coefficient in the base layer) position. 
     
     
       20. The method of  claim 19 , wherein the codebook table information comprises a codebook selection table mapping cycle number. 
     
     
       21. The method of  claim 19 , wherein the codebook table information comprises a table shape and a table dimension and wherein the table shape is rectangular or triangular. 
     
     
       22. The method of  claim 16 , wherein a codebook selection table is dynamically determined from at least one of a statistics estimation and a neighboring correlation. 
     
     
       23. An electronic device that is configured to code significance coefficients in a video sequence, the electronic device comprising:
 a non-transitory computer readable medium having stored thereon executable instructions; 
 means for electronically receiving a video sequence; and 
 means for processing the electronically received video sequence in response to executing the instructions stored on the non-transitory computer readable medium to:
 construct a prediction of an original video sequence in a current frame from the video sequence; 
 form a residual frame by subtracting the prediction of the original video signal from the original video signal in the current frame; 
 apply a transform to the residual signal; 
 quantize a plurality of transform coefficients; 
 select a codebook from a plurality of codebooks to code at least one of a significance run and end-of-block; and 
 code the at least one of the significance run or the end of block using the selected codebook. 
 
 
     
     
       24. An electronic device that is configured to code significance coefficients in a video sequence, the electronic device comprising:
 a memory configured to store at least part of an video sequence; and 
 a video processor configured to:
 construct a prediction of an original video sequence in a current frame from the video sequence; 
 form a residual frame by subtracting the prediction of the original video signal from the original video signal in the current frame; 
 apply a transform to the residual signal; 
 quantize a plurality of transform coefficients; 
 select a codebook from a plurality of codebooks to code at least one of a significance run and end-of-block; and 
 code the at least one of the significance run or the end of block using the selected codebook. 
 
 
     
     
       25. An apparatus for decoding significance coefficients in an encoded video sequence comprising:
 a memory configured to store at least part of an encoded video bitstream; and 
 a video processor configured to:
 retrieve codebook table information from the bitstream; 
 decode significance symbols using the retrieved codebook table information; 
 decode significance coefficients using the significance symbols; 
 dequantize a plurality of transform coefficients; 
 apply an inverse transform to a residual signal; construct a video sequence in the video decoder. 
 
 
     
     
       26. A non-transitory computer-readable medium having stored thereon instruction that when executed by a processor cause the processor to:
 retrieve codebook table information from the bitstream; 
 decode significance symbols using the retrieved codebook table information; 
 decode significance coefficients using the significance symbols; 
 dequantize a plurality of transform coefficients; 
 apply an inverse transform to a residual signal; construct a video sequence in the video decoder. 
 
     
     
       27. A method of coding significance coefficients in a video sequence comprising:
 receiving a video sequence in an electronic video coder; constructing a prediction of an original video signal in a current frame from the video sequence; 
 forming a residual signal by subtracting the prediction of the original video signal from the original video signal in the current frame; 
 applying a transform to the residual signal; 
 quantizing a plurality of transform coefficients associated with the transforn; 
 selecting a codebook from a plurality of codebooks to code a significance run associated with the coefficients; 
 coding, using the selected codebook by the video coder, the significance run to generate a portion of an encoded video bitstream; and 
 outputting the generated portion of the encoded video bitstream from the electronic video coder. 
 
     
     
       28. The method of  claim 27 , further comprising coding an end-of-block using the selected codebook to further generate a portion of the encoded video bitstream. 
     
     
       29. The method of  claim 27 , wherein the codebook table information comprises a pruned table having a table shape and a table dimension. 
     
     
       30. The method of  claim 29 , wherein the table shape is rectangular. 
     
     
       31. The method of  claim 29 , wherein the table shape is triangular. 
     
     
       32. The method of  claim 27 , further comprising coding the selected codebook using a variable length code (VLC).